The primate visual and oculomotor system allows tracking of small visual objects and large moving visual scenes to support optimal visual acuity and visual motor behavior. We use volitional smooth pursuit (SP) eye movements and reflex-like optokinetic (OKR) eye movements to support visual function. Both classes of tracking eye movements require cerebral cortical processing of visual inputs to create initial commands for eye movements. Volitional SP and OKR behaviors offer important perspectives on neural mechanisms that produce sensory-motor behavior, perception and cognitive processing. Our studies focus on the frontal eye fields (FEF) and parietal cortex (MSTd, MSTl, MT), which have been shown to play a role in SP, OKR and perception. However, the information passed between these areas during tracking eye movements remains unknown. Our studies will address this gap in knowledge by providing the first comparative data on visual, eye movement and task related signals carried in feedforward and feedback pathways between frontal and parietal cortex. We will apply novel computational approaches for data analysis, model the functional contributions of frontal and parietal cortex to tracking eye movements, and finally test the model predictions using electrical stimulation and optogenetic techniques to reversibly perturb signaling in this cortical-cortical network. There are extensive cortical-cortical connections between brain regions but we lack specific information about the role of these connections in complex sensory-motor behavior. Our studies are organized under 3 specific aims to experimental and computational approaches that build on information theory and related statistical methods to account for how different signals (e.g., visual, eye movement) are combined and interact to support purposeful behavior. Our experimental work provides novel neurophysiological data taken from frontal and parietal cortical neurons that we identify as projecting from one brain region to another and 2) the experimental results will be directly compared to simulations developed in computational models of cortico-cortical interaction. Our studies have particular intellectual merit in comparing and contrasting different computational approaches for analyzing frontal and parietal cortical neurons simultaneously. We are developing computational models that are capable of predicting eye movement output using neuronal tuning functions determined experimentally. Scientific: In our study we will extend existing, as well as develop novel computational approaches for analyzing dependencies between neuronal firing and behavior. Advancing our understanding of how different cortical areas interact to support sensory-motor transformation and perception has broad scientific applications in normal and pathological neural systems. For example, white matter lesions commonly seen in the aging brain and in other disorders of cortical-cortical communication are poorly understood. Our studies could contribute fundamental knowledge to advance brain-driven neuronal prostheses. Our work could also improve our diagnostic possibilities for eye movement deficits. Dissemination: Our studies take place at the University of Washington's National Primate Research Center (WANPRC) in Seattle and at the Ludwig-Maximilians-University (LMU) in Munich. WaNPRC and UW are known for excellence in primate neuroscience research. The LMU is ranked among the best German universities. LMU was among the first to establish the Bernstein Center for Computational Neuroscience (BCCN) in Germany. Both of our respective institutions are known as leading centers for research and teaching in neuroscience. The LMU is hosting the Graduate School for Systemic Neuroscience (GSN). The UW reaches out to broader academic community at multiple levels through e.g., the multi-disciplinary Neurobiology and Behavior program and Center on Human Development and Disability (CHDD). Outreach: The PIs are actively involved in their institutions' research and teaching missions. This allows us to provide experimental experience and training for computational scientists in Munich and training in computational research for experimental scientists from UW in Seattle. We provide opportunities for students, postdoctoral fellows and mature scientists through group meetings where results will be presented to a broader audience. The PIs and Co-Is are actively involved in local science and clinical translation.